1) Field of the Invention
This invention relates to a tape carrier package, a mounting process thereof and a mounter therefor.
2) Description of the Related Art
The basic technique of tape carrier packages (TCPs) is disclosed in U.S. Pat. No. 3,689,991, which is incorporated herein by reference.
The fundamental structure of the TCP available now on the market follows the above U.S. patent. The TCP disclosed in the above U.S. patent comprises a device hole for mounting a chip, namely, a semiconductor integrated circuit device therein, inner leads extending into the device hole, an outer lead hole for exposing outer leads for use in mounting the TCP on a substrate, conductors connecting the inner leads and the outer leads and a flexible resin tape supporting the conductors thereon. The above U.S. patent also states that the outer leads extend over the outer lead hole.
TCPs based on the technique of the above U.S. patent are used in electronic calculators, watches, liquid crystal displays and the like, and their applications are spreading further. For semiconductor circuit devices in industrial equipment such as computers, higher integration and scale enlargement as well as high-density mounting are required. Conventional pin grid arrays (PGAs) or quad fiat packages (QFPs) are therefore facing increasing difficulties in meeting such requirements, resulting in a tendency toward the adoption of TCPs which permit high-density mounting.
To bond a TCP to a substrate, thermocompressing bonding is commonly employed. According to this bonding method, the TCP is placed at a prescribed location on the substrate, and a hot heating tool is then pressed against each outer lead exposed in an outer lead hole so that solder applied in advance to the lead or the substrate is melted to bond the TCP to the substrate.
This conventional technique, however, involves a potential problem that, when the heating tool is pressed against individual outer leads, differences may arise in the melting time of the solder among the leads due to warpage or the like of the tape. A horizontal force may then be produced so that the leads would be shifted relative to the substrate and, in some instances, would contact an adjacent pad. In addition, due to the narrow and thin configurations of the outer leads, the leads may be deformed upon thermocompression bonding.
Because of this, the conventional technique is accompanied by the problem that the yield becomes low when multipin, narrow-pitch TCPs are mounted on substrates. This problem is particularly serious in industrial equipment such as computers as these types of industrial equipment use multipin, narrow-pitch TCPs.